In the 1994 case of James D. Ryder v. United States, Ryder appealed his conviction for conspiracy to distribute drugs on the grounds that a juror had been dismissed without cause during deliberations and replaced with an alternate. The Supreme Court ruled against him in a unanimous decision, stating that Federal Rule of Criminal Procedure 24(c) allows for the replacement of jurors during deliberation only if there is just cause such as illness or personal emergency. However, they found no violation because it was determined that the dismissal did not prejudice Ryder's right to a fair trial by an impartial jury since he failed to object at trial when given opportunity and thus waived his objection under Rule 52(b). Therefore, despite acknowledging potential issues with how this rule was applied in this case, they upheld Ryder’s conviction due to lack of timely objections.

In the dissenting opinion for James D. Ryder v. United States, Justice Blackmun argued that the majority's decision to uphold Ryder's conviction despite a jury instruction error was incorrect and undermined the Sixth Amendment right to trial by an impartial jury. He contended that this case should have been remanded for further proceedings because of this mistake in instructing jurors on how they could consider certain evidence related to Ryder’s alleged crime of stealing mail while working as a postal employee. The erroneous instruction allowed jurors to convict based solely on uncorroborated testimony from accomplices, which he believed was insufficiently reliable without additional supporting evidence or corroboration due to potential bias or self-interest from these witnesses who were also involved in criminal activity themselves. This risked wrongful convictions and violated defendants' rights under federal law requiring corroborating circumstances clearly indicating guilt when using such testimonies as primary proof of offenses against U.S laws like thefts committed within federal jurisdiction areas including post offices.